FI107547B - Drier assembly of a drier section in a papermaking or board-making machine and drier section in a papermaking or board-making machine - Google Patents

Abstract

The invention relates to a drier assembly of a drier section in a papermaking or board-making machine, which assembly comprises at least one blow-dry unit 30, for drying a paper or cardboard web W, and a drier wire 13 by whose support the web W is arranged to be led past the blow-dry unit(s). The blow-dry unit(s) 30 are situated on the outer side of a loop, formed by the drier wire 13, and a body structure 60 of the drier assembly R, which body structure supports devices situated within the wire loop 13 and rolls which guide and support the course of the wire 13, and the web W is situated within the drier wire loop 13 formed by the drier wire 13. The invention also relates to a drier section in a papermaking or board-making machine, which section comprises at least one blow-drying-based drier assembly R, which has at least one blow-dry unit 30 for drying a web W and a drier wire 13 by whose support the web W is arranged to be led past the blow-dry unit(s). The drier section comprises at least one drier assembly R according to the invention. <IMAGE>

Description

107547

Paper or board machine dryer section drying group and paper or board machine dryer section

Torkningsgrupp av torkningsparti i en pappers - eller cardboard mask and torkningsparti i en pappers - eller cardboard mask 5

The invention relates to a drying group of a drying section of a paper or board machine according to the preamble of claim 1.

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The invention also relates to a drying section of a paper or board machine according to the preamble of claim 10.

As is known in the prior art, multi-cylinder dryers of a papermaking machine use a twin-wire feeder 15 and / or a single-wire feeder. In a two-wire delivery, the drying cylinder groups have two wires which press one of the webs above and one below against the heated cylinder surfaces. Between the rows of drying cylinders, generally horizontal rows, there are free and innumerable strokes on the web which are exposed to flutter, which may cause web breaks, especially when the web is still relatively damp and consequently weak. As a result, there is a growing trend to utilize said single-wire threads, with each dryer cylinder group having only one dryer wire in support of which the web passes through the entire group: such that the dryer wire presses the web against the heated cylindrical surfaces of the drying cylinders side. Thus, in a single wire feed, the drying cylinders are outside the wire loop and the pivoting cylinders or rollers 25 are inside. One problem with these known solutions is the fouling cylinders and rollers outside the wire loop, which is why they have had to - be equipped with scrapers to keep the surfaces clean.

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As the speeds of the papermaking machines increase, the runnability of the papermaking machine will naturally also be affected by the drying section, which would be extremely long at high speeds using previously known multi-cylinder dryers. If the current multicylinder dryer was to be operated at a web speed of 40 m / s, it would have about 70 drying cylinders and its machine length would be ~ 180 m. This would have about 15 different wire groups and an equivalent number of group inlets. It is expected that in the velocity range of 30-40 m / s, the runnability of standard prior art multicylinder dryers would not be good due to open exports, which could result in paper machine efficiency reducing line-5 breaks. Thus, at speeds in the range of 30-40 m / s and above, the prior art multi-cylinder dryers would also be uneconomical because of the high investment costs of an oversized paper machine room. The drying sections made up of multi-cylinder dryers are also often quite high.

In addition, in known applications, the drying groups require the use of machine-seamable wires due to the closed frame structure. A machine-seam welded seam may cause a discontinuity in the drying of the web during the drying process. In addition, the seam welded on the machine-welded wire may limit the wire tension used.

15 Other problems that are becoming more pronounced at high speeds of the papermaking machine, for which at least not all have been satisfactorily resolved, are the quality problems associated with the uniformity of both the machine and transverse properties of the paper web. The smoothness of the web being manufactured also affects the runnability of the entire paper machine and is also an important factor in the quality of the finished paper. The implementation of high speeds, especially on le-20 knife machines, thus presents more difficult problems to solve, the most important of which are machine runnability and sufficient drainage capacity at high speeds.

One problem with paper machine dryer parts when using traditional multi-cylinder dryer parts is the noise they cause. In addition, steam drying is required when cylinder drying is used, whereby the drying cylinders have to be sized according to pressure vessel regulations, and in addition, the hood placed around the drying section must be thermally insulated.

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It is known from experience that if the paper is dried one-sided, the sheet 30 will tend to curl. When paper is dried with normal single-wire threading groups on its underside side, and if such asymmetric drying is extended over substantially the entire length of the dryer section, drying occurs first with the lower surface of the web drying and as drying progresses to the upper surface of the web. As a result, the dried paper generally curves from above, concave.

With reference to the prior art relating to the invention, reference is made to FI patent publication 102623, which discloses a method in a paper machine or the like, wherein the web or the like is dewatered by a press and dried after at least one drying group based on blow-drying or the like. In this known solution, the web is guided substantially linearly or using a large radius of curvature, and in the drying step, after the blow-drying, the web or the like is dried in at least one drying group employing standard single-wire threading and the web is guided from Various types of applications for placing blow-drying units on the drying section are disclosed in the above-mentioned patent and reference is also made to the article by Markus Oeschle in "Drying concepts for high demands", Paper and Wood, Vol. 81, No. 8/1999.

The object of the invention is to provide a drying section and a drying group in which the disadvantages and problems known from the prior art discussed above are eliminated or at least minimized.

It is a further object of the invention to provide a drying section concept which makes it possible to implement shorter and lower drying sections compared to previously known drying sections.

It is a further object of the present invention to provide a drying section in which a good running time and a substantially sealed export of the web can be realized.

It is a further object of the invention to make it possible to implement a drying section concept which provides good paper quality and sufficiently undisturbed runnability.

It is a further object of the invention to provide a drying method and a drying section applying it wherein the web is reliably attached to the drying fabric along the entire length of the drying section such that its transverse shrinkage is substantially prevented and thus uneven transverse shrinkage occurs.

A further object of the invention is to provide a drying group and a drying section in which the frame structure is of a new type allowing the formation of compact drying groups and a drying section.

Yet another object of the invention is to provide a drying assembly in which a pre-fabricated dryer wire loop is threaded in the transverse direction of the machine.

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It is therefore an object of the present invention to provide new solutions to the problems discussed above so as to substantially eliminate the aforementioned and later disadvantages in the art.

In order to achieve the foregoing and further objects, the drying group according to the invention is essentially characterized by what is stated in the characterizing part of claim 1.

The drying section according to the invention, in turn, is essentially characterized by what is stated in the characterizing section of claim 10.

. According to the invention, the drying groups of the drying section are formed of at least one over-blow drying unit for direct drying of the web, i.e. the drying blows are directed directly, not through the wire, and the wire supporting and guiding the web passage is on the opposite side of the web. Within the wire loop is a frame structure housed within the wire loop to support internal wire and web conducting and guiding components and devices, preferably all of the said wire loops. components and equipment. The frame structure supporting the group is preferably disposed so that the main direction of the group is obliquely to the horizontal. Due to the new type of group-30 structure, the dryer section is made low and short and the groups are preferably spaced relative to one another, whereby the length of the dryer section is further shortened. According to a preferred embodiment of the invention, in the drying section, the drying groups are disposed so that one side of the web is dried first and then the other side so that there is no one-sided tendency to warp.

According to the invention, when the dryer section is formed, there is no opening friction between the cylinder and the wire, which would limit the speed, but the drying groups are disposed so that the inter-group export is closed.

In the invention, the web to be dried is preferably supported by vacuum devices, e.g. blowing or suction boxes and / or suction rolls, to further improve runnability while assisting in preventing the web from shrinking.

When applying blow-drying, the drying section does not require steam so that the hood can be constructed simpler as it does not need to be insulated. The blow-drying is also quieter than the cylinder drying, whereby the sound insulation of the hood is also easier to implement.

Because blow-drying is more effective than multi-cylinder drying, the drying section is shorter compared to the drying section formed from the multi-cylinder dryers. In addition, blow-drying is faster than multi-cylinder drying at start-up of 20 paper machines.

In the arrangement according to the invention, there is less rotating mass compared to conventional multicylinder drying, thereby minimizing the problems caused by vibration. In addition, the foundation design is therefore cheaper and the foundation can be made lighter.

In combination with the drying groups of the dryer section according to the invention, a combination of a guide-tensioner device is preferably used, which device both controls the flow of the wire and tightens it to the desired tightness.

30

The drying groups of the invention are compact due to their new type of frame structure, whereby shorter, factory-sewn wires can be used, since the frame of the drying group 107547 can be rolled, i.e. carried for threading the wire loop. In addition, the factory-sewn dryer wire loop can be practically considered seamless, since the fabric structure of the wire loop is flat and does not cause a discontinuity in the drying of the web. In addition, fabric-woven fabrics can use a higher fabric tension 5 than machine-sewn fabrics.

In a preferred embodiment of the invention, no rolls or cylinders outside the wire loop are needed, and no scrapers are required.

According to the invention, all or part of the dryer section may be formed from at least one drying group according to the invention and, if desired, the drying groups according to the invention can be used with conventional multicylinder drying groups or other types of drying groups on the drying section.

The invention will now be described in more detail with reference to the figures in the accompanying drawings.

Figure 1 schematically shows an embodiment of a drying group according to the invention.

Fig. 2 schematically illustrates an embodiment of the invention as a part of a drying section formed of drying groups according to the invention, one and a fourth of which are drying groups. an external roller is used.

Figure 3 schematically illustrates another embodiment of a portion of a drying section formed by drying groups according to the invention, wherein no external rollers are used in the drying groups.

Fig. 4 schematically illustrates an embodiment of the invention in which the drying groups according to the invention are followed by a multi-cylinder drying group.

Figure 5 schematically illustrates an embodiment of the invention using a drying group according to the invention between multicylinder drying groups.

30 7 107547

Fig. 6 schematically shows an embodiment of a carrier frame of a drying group according to the invention.

In the following, a drying group according to an embodiment of the invention will be described with reference to Fig. 1. Figs. 2-4 use drying groups R according to Fig. 1, which may be in the position shown in Fig. 1 or as shown in the Figures in an inverted position. In the normal position, as shown in Fig. 1, the blow-on units of the drying group R are below the group 30 and in the inverted position, such as the other groups of 2,3,4 and 5 of Fig. 10, the blowing units are located above the group.

As shown in Figure 1, the drying group R comprises overflow units 30 disposed outside the loop formed by the wire 13, on the outer surface of which the wire W passes, supported by the wire 13, between the inlet and / or blow boxes of the airblock units 30 and vacuum. Inside the wire loop 13, support rolls 32 are attached to the frame structures 60 to support the passage of the wire 13 and also web W and vacuum-boosting devices, e.g. suction and / or puff boxes 33, are provided between the support rolls 32. . The wire loop 13 is disposed outside the frame structure 60, which frame 20 supports all rolls 31.32.52 of the drying group R inside the wire loop 13 and the devices 33,65,66,67,68 for controlling and / or supporting the web W and the wire 13. -. kua. The frame structure 60 is formed by two beam-like arms 61,62 extending in substantially opposite directions, with rolls 31.52 disposed at each end of the arm to secure the passage of the wire 13 and the web W. The roller 31 is a transfer roller 31, e.g., a transfer suction roller having one or more suction zones. Roll 52 is a folding roll 52, e.g. a suction roll and preferably a roll of the type marketed by the Applicant under the trade name VacRoll ™ or, for example, a suction roll with at least one suction zone. The main direction of travel of web W is indicated by the arrow arrow K and, e.g., a profile adjusting device, a blowing unit or the like 34 is disposed on the trailing side of the roll 52, the wire 13 being guided and tightened 30 by a guide-tensioner combination device 65 68, e.g., a pressure cylinder, and wherein in the combination device 65, the position of the tensioning roller 66 is adjusted by the actuator 68 such that the wire tension 8 107547 is appropriate. The shape of the wire loop 13 is substantially oval and on the drying side the web W runs on its long curved side and the radius of curvature of the curvature is indicated by s. The radius of curvature s = 5-50 m, preferably s - 10-30 m. α and α = o-60 °, preferably δ α = 5-30 °.

In this specification, the principal direction T of the group R refers to the direction T of the plane passing through the central axis of the rollers 31.52 located substantially opposite to the supporting arms 62,61 of the frame 60. The angle α may be formed either upwards or downwards from the horizontal 10 pin. last drying group R).

In addition to the embodiment shown in Figure 1, the invention also encompasses drying groups R having a different number of blowing units 30 than shown in Figure 1. The drying group R according to the invention preferably includes at least one blowing unit 30, 15, preferably 2 to 8. In the embodiment shown in Figure 1, the blowing units are below the wire loop 13, and as shown in Figures 2-5, the blowing units 30 are above the wire loop 13. The drying blows of the blowing units 30 are thus directed directly, not through the wire 13, to the surface of the web W. The blowing units 30 are supported on the machine frame structures (not shown in the figures 20) other than the frame structure 60 located inside the wire loop 13 of the drying group R.

The following Figures 2-6 illustrate some embodiments of the invention as drying sections or portions thereof using the drying groups R according to the invention. For the sake of clarity, only some of the components are referenced in the figures since the groups R are substantially the same as the group . * group unless otherwise stated. The same reference numerals denote corresponding parts or sub-assemblies.

In the exemplary embodiment of Figure 2, the web W is guided to the last press nip point P of the press section supported by the press felt 11. The paper W, led by the press felt 11, is led to a press nip P formed by the press roll 15 and its counter roll 16, where the water W is dewatered. The upper press felt 11 passes supported by the guide rolls 25. Below this passes a transfer belt guided by guide rollers 26 or a press felt 12 which runs between the press roll 15 and the counter roll 16. From the press 15,16, the web W is guided to the first group R of the dryer section, which is a drying group R according to the invention. The web W supported by the transfer belt or press felt 12 below the press nip P is guided through the transfer roller 31 to the group R dryer fabric 13. associated support rollers 32 and vacuum devices 33 disposed therebetween. The drying fabric 13 is guided and supported by a guide roller 31, a fold roller 52, support rollers 32 and 10, a guide-tensioner 65. After drying on the blowing roller 30, the web W is led past the folding roller 52 and e.g. the profiling device 34, supported by the wire 13, to the next drying section R. The folding roller 52 is substantially reversed until the first drying section R the transfer roller 53 is rotated on the drying fabric 13 of this next drying group R to travel in the main travel direction K to the blowing units 30 for drying. For example, a profiling device 34 is provided in connection with the transfer roller 53, which may be e.g.

The next group R is inverted with respect to the previous group, whereby it dries one side of the 20 W web. The drying group R includes overflow units 30, support rollers 32 disposed therebetween, and a transfer roller 53 and a wire guide roller 41 disposed at a shaft 61.62 of the frame structure 60 and a guide-tensioning device 65. The roller 41 is a wire guide roller 41 and a transfer roller having one or more suction zones. In this group R there is additionally one external wire guide roll 42 connected to the pattern by a scraper 43. The next group R corresponds to the first group R and the last group R shown in the figure corresponds to the second group R, i.e. alternately drying each side of the web W. From the last group R, the web W is passed through the transfer roll 51 to the fabric 14 for further processing or subsequent drying groups which may be drying groups according to the invention or based on multi-cylinder drying.

As can be seen from the figure, the drying groups R are spaced relative to one another, thereby significantly reducing the length of the drying section. Between the first and second groups R, and the like, between the second and fourth groups R, the passage of the web W is reversed substantially opposite to the main travel direction K, while between the second and third groups R the web W is guided substantially in the same travel direction from K to the following. .

5

As shown in Figure 2, each of the drying groups is formed substantially obliquely, and rolls (transfer roller 31.53, fold roller 52, wire guide roller 41) are attached to the free ends of the support members of the frame structure 60 and vacuum structures 33,330 and support rollers 32 are also supported.

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The embodiment of the invention shown in Figure 3 corresponds essentially to that shown in Figure 2 and like parts are denoted by the same reference numerals. In the embodiment of the invention shown in Fig. 3, no external wire guide rolls are used at all, but the wire 13 is guided and guided entirely by the rolls 31,53,32,41,52 and the guide tensioner 65 placed inside the wire loop 13.

As shown in Figure 4, the drying groups R according to the invention can also be combined with conventional multicylinder drying and here is a standard single-wire dryer drying group M located below the drying groups R according to the invention, with rotating rollers marketed by the applicant under the trademark VacRoll ™. overhead drying cylinders 72. The wire rolls are denoted by reference numeral 73 and the drying wire by reference numeral 74. From the last drying group R according to the invention, the web W is guided to a single wire thread through a roll 75, for example a transfer suction roll. kneeling 25 from the drying cylinders 72 to the turning rolls 71 and the drying cylinders 72, the web W is between the drying wire 74 and the heated drying cylinder surface. From the drying group M applying a single wire export, the web W is led through roll 81 to further processing or subsequent drying groups. In Figure 4, the final drying group is used to dry the opposite side of the web W to the previous group R according to the invention.

In the embodiment of the invention according to Fig. 5, a conventional single-wire drying drying group 30107547 M is disposed between the second and third drying groups R according to the invention, wherein the drying fabric 74 runs from rotating rollers 71 to drying cylinders 72 Herein, a single-wire threading group M disposed between the drying groups R according to the invention is on the opposite side to the preceding and following drying group R. The drying group R according to the invention is disposed substantially horizontally between the drying groups M and 5. From the preceding single-wire drainage drying group M, the web W is guided to the drying group R according to the invention via a transfer roller 54.

The arrangement shown in Figures 4 and 5, in which the group employing the normal single-wire thread M is located at the end of the dryer section, is particularly advantageous in that the web W can be driven in a controlled manner to the pulper.

As shown in Fig. 6, the frame structure 60 disposed inside the wire loop 15 13 of the drying group R according to the invention can be folded or carried. The portable run superstructure 60 is supported on the treatment platform 90 on the support beams; the first group on the support beams 91.92 and the second group on the support beams 92.94 and the first group on the frame structure 60. The support beams 91,92,94 and the Frame structures 60 are provided with removable blocks 91A, 92A, 94A, 99A which are removed during the edging, allowing the wire loop 1320 to be threaded around the frame structure 60 as a finished loop, i.e. a factory-welded wire. Edging is known per se to a person skilled in the art in connection with the insertion of the press portion of the tissues and is not described in further detail herein. Accordingly, it is to be noted that the new type of frame structure 60 of the drying group R according to the invention allows for the insertion of a wire loop 13 in connection with the drying group, thereby achieving the previously discussed advantages afforded by the compact drying group according to the invention.

The invention has been described above with reference only to some of its advantageous details, however, it is not intended to limit the invention in any way. For example, the drying groups according to the invention can also be considered to be applied in such a way that Figures 2 or 3 are viewed in an inverted configuration, whereby the main running direction K is from right to left and thus the first drying group R according to the invention dries the upper surface of the web.

Claims (14)

A drying section of a drying section of a paper or board machine, comprising at least one blow drying unit (30) for drying a paper or cardboard web (W) and a drying fabric (13) supported by a web (W) adapted to be conducted through a blowing drying unit (s). 30), characterized in that the blow-drying unit (s) (30) is located outside the loop formed by the drying wire (13) and that the wire (13) and the web (W) are guided and supported inside the wire loop (13) of the drying group (R). the frame structure (60) supporting the devices and rolls is disposed inside the dryer wire loop (13) formed by the drying wire (13). A drying group according to claim 1, characterized in that the main direction of the drying group (R) is substantially oblique to the horizontal at an angle (a) of 2 to 30 °. 15 A drying group according to claim 1 or 2, characterized in that the drying group (R) further comprises vacuum devices (33) disposed on the inside of the drying wire loop (13) on the opposite side of the drying wire (13) and to support and control the passage of the web (W). A drying group according to claim 3, characterized in that support rollers (32) are arranged in connection with the vacuum devices (33). Drying group according to one of Claims 1 to 4, characterized in that the frame structure (60) of the drying group (R) is formed as a portable frame structure supported by beams (91,92,94) arranged on the treatment level (90), wherein the beams are provided with removable pieces (9IA, 92A, 94A) which can be removed during burring, wherein the dryer fabric (13) is looped in place in the machine direction 30. 14 107547 A drying group according to claim 5, characterized in that the body (60) of the drying group (R) is followed by removable bodies (99A) which can be removed during the edging. Drying group according to one of Claims 1 to 6, characterized in that the frame structure (60) of the drying group (R) is formed by two mutually connected extending arms (61,62) with a roll (31,53) at their free end; 52,41) for controlling and / or supporting the passage of the web (W) and the wire (13). A drying assembly according to any one of claims 1 to 7, characterized in that a combined guide-clamping device (65) is attached to the frame structure (60) inside the dryer wire loop (13), comprising a guide roll (65) for guiding the drying wire (13). an actuator (68) for adjusting the tension of the drying wire (13) of the movable tensioning roller (66). Drying group according to one of Claims 1 to 8, characterized in that all the devices and rollers controlling and / or supporting the passage of the wire and the web of the drying group (R) are attached to the frame structure (60) inside the drying wire loop (13). A drying section of a paper or board machine, comprising at least one blow-drying dryer group (R) having at least one blow-drying unit (30) for drying the web (W) and a drying wire (13) supported by the web (W). adapted to be passed past the blowing unit (s), characterized in that the drying section comprises at least one drying group (R) according to any one of claims 1 to 8. 25 Drying section according to Claim 10, characterized in that a plurality of drying groups (R) based on over-drying are arranged in succession so that the opposite sides of the web (W) are dried by successive drying groups (R). A drying group according to claim 11, characterized in that the group intermediate entry between the drying groups (R) is closed. is 107547 Drying section according to one of Claims 10 to 12, characterized in that the drying groups (R) based on the over-drying of the drying section are spaced relative to one another. 13 107547 Drying section according to one of Claims 10 to 13, characterized in that the dry section comprises, in addition to the drying group (s) (R) based on blow-drying, at least one drying group (M) applying standard single-wire drawing. 16 107547